VSetTextOn - turns a Text (Tablet) Item ON.
  TEXT *item;
  VSetTextOn turns a Text (Tablet) Item ON (displays a tablet that was turned
  typedef struct _text {
        Window  win;            /*window in which item resides*/
        GC      *gc;
        int     x,y;            /*location of upper-left corner of item*/
        int     w;              /*width of the total item area in fonts*/
        int     h;              /*height of the total item area in  PIXELS*/
        short   label_width;    /*width of label in pixels*/
        short   label_height;   /*height of label*/
        short   label_ascent;   /*ascent dimension of font*/
        short   label_x;        /*position of the label*/
        short   label_y;
        int     thick;          /*thickness of the frame of the item*/
        int     width;          /*current width of item in pixels*/
        int     fw,fh;          /*size of font*/
        char    label[150];     /*label of the text item*/
        char    value[200];     /*value of the text item*/
        int     pos;            /*pos indicates the index of the first VALUE*/
        int     state;          /*indicates if text item is OFF(0) or ON(1)*/
        int     mode;           /*text item is DISABLED(0) or ENABLED (1)*/
        int     (*func)();      /*notify procedure*/
        struct _text *next;     /*next text item*/
        XFontStruct *font_struct; /*Font used on the window*/
  } TEXT;
Return Value
  0 - work successfully.
  266 - invalid Text Item ID.
  item - Text Item ID.
Side Effect
  The 'state' element of the Text Item's structure is changed. The Text Item
is redisplayed.
Entry Conditions
  VCreateColormap should be called earlier, else VSetTextOn prints an
error message to the standard error stream, produces a core dump file and
exits from the current process.
Related Functions
VAddText, VSetTextOff.